Protect stored grain from insects, mold

Spiking grain prices have inspired some producers to build grain bins for the first time ever or after a lapse of years to capitalize on these premium prices.

And there’s nothing wrong with this strategy, says one Extension expert, providing they know how to maintain grain quality and handle grain safely. On the other hand, not paying attention to these basics could exact a heavy toll, both in terms of their financial bottom lines and even their personal safety.

“Some have never stored grain before, and for others it’s been along time,” says Kathy Flanders, an Alabama Cooperative Extension System entomologist and Auburn University associate professor of entomology, who says that growers may not know or may have forgotten the potentially destructive power of insects.

Growers should never lose sight of this cold, hard fact, she says. Otherwise, all the trouble involved in raising and storing their grain could turn out to be a wasted effort.

Indeed, because of the region’s warm climate, Southern grain bins are especially prone to insect infiltration and molds — the reason why farmers should make every effort to stop them dead in their tracks while bins are still empty.

“We have to be especially careful down here and use all the tools available to make sure the grain is the same quality coming out of the bin as when it goes in,” Flanders says.

And there’s a whole motley crew of insects able to do a job on stored grains — what Flanders describes as the primary pests, which attack healthy, intact kernels, and secondary pests, which feed on particles and grain dust and by their mere presence can degrade the quality of the stored grain.

Likewise, molds — fungi that can attack grains and grain products at any stage of storage — can inflict similar catastrophic damage on the crop.

If there is any good news in any of this, it’s that experts such as Flanders have learned a lot more about controlling pests and molds within the last decade or so.

The first rule of thumb is never to forget most of the insects that can get into your bin already are living somewhere around your storage area.

While a couple of these insect species may be brought in by the combine following harvest, most have been in and around the bin for a long time, she warns.

Also, by their nature, bins, which were built for the easy loading and unloading of grain, or for protecting grain against rain, birds, and rodents, are not well equipped to keep out these pests.

“There are a lot of holes, by design or otherwise, that are going to let in bugs,” Flanders says.

She offers a series of recommendations for dealing with wheat storage.

There’s plenty to do in the way of cleaning out the bins thoroughly to eliminate starter colonies of insects or molds that could threaten the wheat, starting with a thorough vacuuming or sweeping to remove insect debris and remaining grain, she says.

Likewise, unnecessary openings should be sealed with caulk or expandable foam. Duct tape and plastic also may help.

Additionally, an EPA-approved insecticide should be used to spray the floor, inside and outside walls and the concrete pad around the grain bin.

“This so-called empty bin treatment will kill the insects that are there and provide some protection against future invasion,” Flanders says.

Wheat should be stored in the bin at no more than 12-percent moisture content.

The wheat also should be treated with an EPA-approved insecticide as it is loaded into the bin, Flanders says.

Wheat should not be loaded above the vertical sides of the bin, because the slanted head space is needed not only to provide access to the grain but also to allow effective aeration and, if the need arises, to conduct an effective fumigation.

The surface of the grain also should be leveled, because the grain in the peak will be wetter and warmer than the surrounding grain, Flanders says, adding that wet, warm conditions favor the development of insects and molds.

“If the bin doesn’t have a spreader to distribute the grain, this necessarily will involve manually flattening the grain peak,” she says, stressing that safety procedures should be closely followed whenever anyone attempts to set foot on the potentially unstable surface of stored wheat and other grains.

Monitoring is essential once the wheat is in the bin. “Once it’s in the bin, it should be checked at least once a month for insects, using a grain probe or specially designed insect traps,” Flanders says, and fumigation will be necessary if the monitoring turns up insects.

Just remember that while grain bin fumigation is common throughout the South, it is also a process fraught with risk, Flanders says.